Reference gas mixtures are used for calibration of gas analyzers for
environmental measurements. Gravimetric preparation method is one
of the methods to be able to realize high-accuracy gas mixtures. In
this method, concentration of mixture can be calculated from mass
of each component gas. However, the buoyancy effect on large gas cylinder
interferes high-accuracy mass measurement. Then, it is required to
minimizing the effect by an appropriate balance. We have successfully
developed unique equipment that has automatic alternative loading
mechanism of gas cylinders (Mixture and referece cylinders) for mass
measurement with accuracy of several milli grams (Photograph and Figure).
The reference gas mixtures prepared using this equipment have been
validated in the international comparisons, for example, CCQM-P41"Greenhouse
gases".
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| NMIJ Balance for gravimetric
preparation of reference gas mixtures |
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| Result of weighing the difference
between mixture and reference cylinder using NMIJ balance |
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| Relational Information |
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AIST Today Vol. 2, No. 12 (2002) 20
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No.8
Spring 2003
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